Web turning bar device

ABSTRACT

A web turning bar device for turning and transferring a paper web which extends between two web offset printing units having first and second turning bars the axes of which lie in spaced parallel planes 90* to each other and 45* with respect to the paper web and a roller positioned to one side of the turning bars the axis of which lies in a plane midway between and parallel to the planes of the first and second bars where the planes containing the turning bars and roller are inclined positively with respect to a line connecting the first printing unit and midpoint of the turning device and negatively with respect to the midpoint of the device and the second printing unit whereby the paper web leaves the blanket cylinder of the first printing unit tangentially and tangentially touches the impression cylinder of the second printing unit.

United States Patent 1191 1111 3,906,855 Laursen 1 Sept. 23, 1975 WEB TURNING BAR DEVICE 3,730,449 5/1973 Satas et a1 197/133 R [75] ento Oskar F aursen Mon real 3,809,303 5/1974 Brunner 226/197 C d FOREIGN PATENTS OR APPLICATIONS 561,408 8/1958 Canada 226/197 [73] Asslgnee' 2 2 Indusmes Mddlesex 1,039,539 9/1958 Germany 226/197 [22] Filed: June 24, 1974 Primary ExaminerEdgar S. Burr Assistant ExaminerEdward M. Coven [21] Appl' 482l50 Attorney, Agent, or FirmPennie & Edmonds Related US. Application Data 3 [63] Continuation of Ser. No. 327,931, Jan. 30, 1973, ABSTRACT abandoned A web turning bar device for turning and transferring a paper web which extends between two web offset 101/180; printing units having first and second turning bars the 101/257 axes of which lie in spaced parallel planes 90 to each [5 Cl. other and 45 respect to the paper web and 3 r01. [58] Field of Search 101/179, 180, 220-223, ler positioned to one side of the turning bars the axis 101025, 226/197, 199 of which lies in a plane midway between and parallel to the planes of the first and second bars where the 1 References Clted planes containing the turning bars and roller are in- UNITED STATES PATENTS clincd positively with respect to a line connecting the 471,403 3/1892 Southgate 101/223 first Priming unit. and midpoint of the turning device 639,784 12/1899 Southgate 101/257 and g e y with respect to the midpoint of the 752,940 2/1904 Wood 101/225 vice and the second printing unit whereby the paper 2,733,061 1/1956 Crafts.... 226/197 web leaves the blanket cylinder of the first printing 3,042,3 7/ Bierman 4 226/199 unit tangentially and tangentially touches the impres- 3,095,131 6/1963 Robertson et a1. 226/199 i cylinder of the Second printing i 3,300,114 1/l967 Jacobsen 226/180 u 3,623,645 11/1971 Klingler 226/197 1 Cla1m, Drawing Flgures US Patent Sept. 23,1975 Sheet 1 of 2 US Patent Sept. 23,1975 Sheet 2 of2 3,906,855

WEB TURNING BAR DEVICE This is a continuation of application Ser. No. 327,931, filed Jan. 30, 1973, now abandoned.

BACKGROUND OF THE INVENTION The invention relates to a web transfer and turning device or unit used with multi-unit offset printing units which are spaced apart and where one printing unit prints on one side of the web and the second printing unit prints on the other side of the web necessitating the web being reversed between the two units.

DESCRIPTION OF THE PRIOR ART Web transferring and reversing devices or unitsutilizing turning bars are known in the art. Such devices have been used between spaced printing units where one side of the web is printed by one unit and the other side of the web by a-second unit. Such devices have comprised turning bars over which the web passes which are spaced apart and which extend 90 with re spect to each other and 45 with respect to the web travel between the printing units. Such devices in the past have in addition utilized a roller over which the web passeswhich has been positioned to one side of the printing bars with thelongitudinal axis extending parallel to the direction of the web travel. These devices, sometimes known as bay windows, have required the use of additional idler or guide rolls in order to maintain proper print register of the web during the passage between the printing units. This has led to problems in that the fresh print on one side of the paper web would run overv at least one of the idler rolls, and, if the ink were not sufficiently dry, would result in smearing of a freshly printed ink. Further, the inclusion of a web idler roll in association with a turning device required that the printing units be spaced further apart in order to accommodate the idler rolls. This in turn has led to some difficulty where pressroom area is at a minimum.

It is therefore an object of my invention to provide for a web turning unit to be used between two printing units which will eliminate any need for guide or idler rolls and which will still nevertheless maintain proper print register of the web as it passes between the two printing units. It is a further object to provide for a web turning unit to be used between two printing units where the turning bars of the unit are spaced sufficiently apart to clear a straight web lead that may extend from one of the two units to the other such that the turning unit is bypassed.

SUMMARY OF THE INVENTION Broadly, the invention comprises placing a web turning unit between two printing units wherein the turning device comprises first and second turning bars lying in parallel spaced planes where the longitudinal axis of each bar extends 45 with respect to the web travel be- .tween the printing units and 90 with respect to each other and where a roller is positioned to one side of the turning bars with its longitudinal axis lying in a plane parallel to and positioned midway between the planes of the turning bars. All of the planes are inclined with respect to a line joining the printing portion of the printing units such that there is a positive inclination of the planes between a printing unit which has just printed a web and the center of the unit and a negative inclination with respect to the device and the printing unit to which the web is being transferred.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a typical prior art installation illustrating a turning device placed between two printing units and having guide rolls for maintaining proper print register of the web;

FIG. 2 is a side view of a turning unit constructed according to the invention shown positioned between two printing units similar to the units of FIG. 1;

FIG. 3 is a schematic view of the unit shown in FIG. 2, illustrating the paper web bypassing the turning unit in a straight lead'between the two units; and

FIG. 4 is an enlarged perspective view illustrating the passage of a web'of theturning unit of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In order to emphasize the differences between a turning unit'constructed according to theinvention' and that as used in the prior art, reference is made to FIG. 1 which illustrates atypical prior art web turning and reversing device 1 which is shown placed between two printing units 2 and 3 having blanket cylinders B B and impression cylinders I I respectively. The printing unit 2 prints on one side of the paper web 4 whereas the printing unit 3 prints on the opposite side of the web 4. This requires that the web be reversed or turned between the twounits. The turning device as shown comprises a first turning bar 5, the axis of which extends 45 with respect to the web travel between the two printing units. A-second bar 6 extends with respect to bar 5 and'is positioned over bar 5 a sufficient amount that there will be a clearance between the web surfaces passing over the bars. A roller'7 is positioned to one side and in back of bars 5 and 6 and the axis of this roller lies in a plane extending between the axis of bars 5 and 6. The web 4 is guided over bar 5 where it is turned 90, then over roller 7, and then back over bar 6 where it is turned another 90, whereby the web is reversed in the process (that is where the top side containing the printed matter imparted thereon by unit 2 now becomes the bottom side of the web). In order to maintain proper print register and to prevent the web from becoming slack, the prior art device utilized idler or guide rollers 8, 9 and 10 which guided the web from the printing unit 2 which printed the top of the web into the turning device and idler or guide rollers l1, l2 and 13 which guided the web from the turning device to the unit 3 where the reverse side of the web was printed. In the device shown rollers 8, l0 and 13 would become so-called dirt rollers since some of the fresh print applied by unit 2 would be deposited on the surface of these rollers and lead to subsequent smearing of the web. This would also occur in the case of a straight web leading from printing unit 2 to printing unit 3 where it is not desired to reverse the web. Further as shown, the printing units 2 and 3 have to be spaced sufficiently far apart to accommodate both the turning device 1 as well as the rollers 9, l0 l1, and 12.

I have found that the guide rollers as shown in FIG. 1 may be eliminated and proper print register still maintained throughout the web as it moves between the two printing units if the turning unit is inclined to the direction of travel of the web along a line joining the printing portions of the printing units. Thus in FIG. 2 the turning unit as shown comprises a bar 20 which is inclined 45 to the direction of the travel of web 4 between the two units. A bar 21 which extends at 90 with respect to bar is positioned above bar .20' and the axis of the bar extends in a plane parallel to the axis of bar 20. A roller 22 having a diameter which is substantially larger than the sum of the diameters of the two turning bars is positioned to one side of the bars 20 and 21 and its axis extends in a plane positioned midway between and parallel to the planes containing the axes of bars 20 and 21. Further the axis of roller 22 extends parallel to the direction of web travel between the two printing units. Mounting means such as brackets 23 and 24 may serve for mounting the bars 20 and 21 and roller 22 onto the printing units, but other suitable means may be used instead of brackets.

The unit is tilted a few degrees about its geographical center C in a clockwise direction as shown in FIG. 2 so that all of the planes containing the axes of bars 20 and 21 and roller 22, which planes are all parallel to each other, have a positive inclination P at the web entry side of the unit with respect to a horizontal straight line joining the printing portions 25 and 26 of the printing units and a negative inclination N at the web exit side of the unit with respect to the straight line. The tilting can be effected by moving mounting means 23 upwardly a small amount and mounting means 24 downwardly an even amount. It is an essential requirement in this structure that the paper web leaves the blanket cylinder B of theprinting unit 2 tangentially and arrives tangentially at the impression cylinder l of printing unit 3.

The bars 20 and 21 are spaced apart vertically a sufficient distance to allow a straight web to lead directly from unit 2 to unit 3 between the bars without the necessity of using any idler or guide rollers which might result in offset or ghost printing. This arrangement of having the web extend directly between the two units and by passing the turn bars would occur when the web is to be printed on one side with two colors. The maximum tilt angle must not exceed that whereby the turning bars would contact a straight lead of a web when the web extends directly between the printing units to by pass the turning unit.

Elimination of the idler rolls allows the units 2 and 3 to be spaced closer together. This can be an important feature when pressroom floor area is limited as may arise, for example when additional printing units are added into an existing pressroom.

I claim:

1. In a web offset printing machine having first and second printing units spaced apart, and a web turning unit positioned between said printing units and along a horizontal line connecting the printing portions of each said printing unit adapted to turn and transfer a paper web extending between said printing portions where said turning unit has a first turning bar the longitudinal axis of which lies in a first plane and extends at approximately 45 to the direction of web travel between said printing units, a second turning bar positioned above said first bar with the longitudinal axis of said second bar lying in a second plane parallel to said first plane and at approximately to said first plane, and a roller positioned to one side of said first and second bars with the longitudinal axis of the roller lying in a third plane midway between and parallel to said first and second planes and at approximately 45 to said first and second turning bars, the improvement comprising in that said turning unit is inclined with respect to said horizontal line with the inclination of the planes containing the turning bars and roller forming a positive angle with respect to a portion of said horizontal line extending between the turning unit and said first printing unit and forming a negative angle with respect to the portion of said horizontal line extending between said turning unit and said second printing unit and where the angle of inclination does not exceed that whereby the turning bars would contact a straight lead of web extending directly from the printing portion of said first printing unit to the printing portion of said second printing unit. 

1. In a web offset printing machine having first and second printing units spaced apart, and a web turning unit positioned between said printing units and along a horizontal line connecting the printing portions of each said printing unit adapted to turn and transfer a paper web extending between said printing portions where said turning unit has a first turning bar the longitudinal axis of which lies in a first plane and extends at approximately 45* to the direction of web travel between said printing units, a second turning bar positioned above said first bar with the longitudinal axis of said second bar lying in a second plane parallel to said first plane and at approximately 90* to said first plane, and a roller positioned to one side of said first and second bars with the longitudinal axis of the roller lying in a third plane midway between and parallel To said first and second planes and at approximately 45* to said first and second turning bars, the improvement comprising in that said turning unit is inclined with respect to said horizontal line with the inclination of the planes containing the turning bars and roller forming a positive angle with respect to a portion of said horizontal line extending between the turning unit and said first printing unit and forming a negative angle with respect to the portion of said horizontal line extending between said turning unit and said second printing unit and where the angle of inclination does not exceed that whereby the turning bars would contact a straight lead of web extending directly from the printing portion of said first printing unit to the printing portion of said second printing unit. 